Hey everybody! I know it has been a while since we did a post, but we’re trying to get back at it. Today we’re going to talk about wobbly cats! I am the parent of a very mildly wobbly cat named Hemsworth, or Hemmy for short. He also happens to be deaf. Before adopting Hemmy I had seen wobbly cats online through social media, I even followed @littleman_mika with CH cat Little Man. However, when I took in Hemmy I knew I had some things to learn about what it actually meant to be a wobbly cat parent.
When I say wobbly cat, I mean a cat who has trouble with coordination and walking. The more accurate label for this is ataxia. Ataxia is defined as “incoordination, wobbliness or unsteadiness due to a failure to regulate body posture and the strength and direction of limb movements.” The word comes from two root words: a- meaning lack and -taxia meaning order. Basically, ataxia means a lack of order. Ataxia is the most common neurological issue found in cats. What we’re specifically looking at is the way they walk. There are three main types of ataxia based on where in the nervous system the problem is occurring: cerebellar, vestibular, or sensory.
Cerebellar ataxia means the wobbles come from something related to the cerebellum. The cerebellum is a part of the brain, at the back, with an important role in balance and in controlling and regulating movements of the limbs, body, and head. In particular, the cerebellum coordinates fine motor movement like control of eyeball position. With cerebellar ataxia, motor strength is unaffected, meaning the strength of the muscles to move is unaffected. It is how they move that is different. Cats with cerebellar ataxia often look normal when resting but when they move their limb movements can be exaggerated and they typically have head tremors. This form of ataxia is often present from birth, though it can also be brought on by damage or inflammation to the brain.
Some common causes of cerebellar ataxia include:
Stroke or blunt trauma (with bleeding of the brain)
Exposure to toxins or infection before birth
Viral infection (like feline infectious peritonitis (FIP))
Parasitic infection (like toxoplasmosis)
Vestibular ataxia means the wobbles come from something related to the vestibular system, which is responsible for controlling the position of the head, body, and eyeballs. Specifically, it means there is a lesion or injury affecting the vestibular system. Symptoms of vestibular ataxia will occur on the same side of the body where the lesion is located and may include a head tilt, falling, rolling, vomiting, involuntary darting of the eyes back and forth, one eye appearing to look off at a different angle from the other eye, deafness, or facial nerve paralysis. As with cerebellar ataxia, motor strength is unaffected. The lesion of vestibular ataxia can be located either within peripheral vestibular areas (meaning the inner ear or auditory vestibular nerve) or in the brain (meaning the vestibular nuclei of the brainstem or the thalamus). These are respectively known as peripheral vestibular syndrome and central vestibular syndrome.
Some common causes of vestibular ataxia include:
Bacterial ear infection
Fungal ear infection
Nasal cavity or soft palate polyps
Tumors in the ear or skull
Trauma to the head/ear
Lastly, and probably the hardest for me to explain as a layman, sensory ataxia means the wobbles come from something related to the ascending sensory tracts in the spinal cord, most commonly the general proprioceptive tracts. The ascending tracts are the neural pathways that transmit sensory information from the peripheral nerves to the cerebral cortex. More simply, the ascending tracts transfer sensory information (like the feeling of heat) from, say, the paw pads to the brain. The proprioceptive tracts support the body’s unconscious awareness of where the body is located within space, what makes sure the cat doesn’t run into something while walking. In sensory ataxia a lesion is located within the spinal cord, usually in the upper cervical (spinal) area, and affects all fours limbs. If the lesion occurs further down in the spinal cord then just the lower limbs may be affected or the body’s motor strength will be affected.
Some common causes of sensory ataxia include:
Tumor on the spine
Degenerative myelopathy (loss of spinal cord tissue)
Now that we know what the forms of ataxia are, let’s take a closer look at a few of the common causes.
Feline Infectious Peritonitis (FIP)
Feline Infectious Peritonitis (FIP) is an uncommon result of the feline coronavirus (FCoV) infection. Almost every cat is exposed to coronavirus at some point in their lives, but most cats simply become infected, shed the virus for a month or two, develop an immune response, eliminate the virus, and live perfectly normal lives. However, for reasons doctors don't fully understand, some cats develop FIP. The symptoms the cat develops depend on which blood vessels are damaged and which organ(s) those damaged blood vessels supply.
Wet (or effusive) FIP is the acute form of the disease where many blood vessels are severely damaged and fluid leaks out of them into the abdomen or the chest cavity. When the blood vessels in the abdomen are affected the cat's stomach fills with fluid. When the blood vessels in the chest are affected fluid leaks into the chest and the cat has difficulty breathing.
Dry (or non-effusive) FIP is the more chronic form of the disease. In dry FIP, the cat often has nonspecific symptoms such as decreased appetite, losing weight, or the fur looking dull. Many cats with dry FIP become jaundiced such that when you look inside the eyelid it looks yellow or, if the cat has a pale nose, you may notice the nose looks yellow. Many cats with dry FIP get signs in their eyes: usually the iris (the colored part of the eye around the pupil) changes color and parts of it may appear brown. The cat may bleed into the eye or white areas may appear on the cornea (the clear membrane on the front of the eye). Around 12% of cats with dry FIP develop neurological signs. For cats younger than two years or older than nine years, symptoms of progressive ataxia are common with dry FIP. Cerebellar signs are the most common but vestibular signs, seizures, and lower limb ataxia are also common. These cats also usually develop a fever, depression, or eye inflammation.
Cerebellar Hypoplasia is most commonly caused by an in-utero (in the womb) infection of pregnant cats with the panleukopenia virus (also known as the distemper virus). The panleukopenia virus has cytopathic effects (CPE) on rapidly dividing cells. More simply, panleukopenia causes rapidly dividing cells to die or stop reproducing. During the last few weeks of pregnancy and the first weeks after birth, the cerebellum of a kitten is undergoing rapid growth and development making it vulnerable to the virus (lots of cells rapidly dividing). As a result, the cerebellum of affected kittens is underdeveloped.
Any number of kittens in the litter may be affected with a varying degree of severity. For instance, Hemmy was the only kitten in his litter to have ataxia. Symptoms first become apparent when the kitten begins to walk at around two to three weeks of age and the severity depends on how much the cerebellum was affected and at what stage in its development the infection occurred. The symptoms are non-progressive and sometimes improvement can be seen as the kittens compensate through other senses. The most typical symptoms are jerky or uncoordinated walking, swaying from side to side when trying to walk, a goose-stepping walk (hypermetria), mild head tremors, or intention tremors, tremors that occur when the kitten is focusing on a particular movement like eating out of a bowl or playing with a toy.
Idiopathic Vestibular Syndrome
This common cause of peripheral vestibular syndrome in cats has a sudden onset with no apparent cause. It’s a condition in which a cat suddenly develops incoordination, begins falling or circling to one side, involves involuntary darting of the eyes back and forth (nystagmus), a head tilt, and nausea or vomiting. These symptoms usually appear suddenly, many times in less than an hour. Affected cats are usually young to middle-aged and generally improve in two to three days, although residual effects (especially head tilt) may take some time to improve. Some cats may be left with a permanent head tilt. No cause has been identified so if other neurological problems are identified then other causes should be considered.
Otitis media is a group of inflammatory diseases of the middle ear and otitis interna is inflammation located in the inner ear. These common causes of vestibular ataxia are usually produced by ear canal inflammation protruding into the middle and inner ear. Foreign bodies in the external ear canals (like grass awns) may penetrate the eardrum or cause a chronic inflammation of the ear canal with rupture of the eardrum. If there is no ear canal inflammation, infection can spread through the small passageways that connect the throat to your middle ears (Eustachian tubes) or it can be spread by the blood. The most common infectious agents are bacteria. Ear mites can also result in a rupture of the eardrum and a secondary otitis media/interna.
The symptoms associated with otitis media/interna usually have a sudden onset and there are usually secondary symptoms related to the ear infection like discharge from the ear with head shaking, scratching or rubbing of the ears, or frequent yawning. A partial recovery may be possible as the cat compensates for the changes over the next day or two and the outcome is generally good with a prolonged course of the right oral and topical antibiotics.
Middle ear polyps are a possible cause of vestibular ataxia in cats when there is a sudden onset of peripheral vestibular signs and there are symptoms indicating a middle/inner ear disease. Affected cats are usually young at the time the symptoms appear (less than two years old). The polyps may be situated in the external ear canal and/or within the nasopharynx (the upper part of the throat that lies behind the nose). The majority appear to originate in the Eustachian tubes which results in a blockage of drainage from the middle ear leading to symptoms of ear disease.
Diagnosis may require examination of the external ear canal, eardrum, and throat under general anaesthesia, and imaging of the middle/inner ear by either radiography or MRI. In some cases exploratory surgery is required. The polyps are usually only attached by a narrow stem to the Eustachian tube and can easily be removed.
Aminoglycosides are a class of antibiotics used to treat serious infections caused by bacteria that either multiply very quickly or are difficult to treat. Aminoglycosides are called bactericidal antibiotics because they kill bacteria directly. They accomplish this by stopping bacteria from producing proteins needed for their survival. Because aminoglycosides are normally used to treat serious infections, they are typically administered into the veins of the body (intravenously, or IV). However, some aminoglycosides can be taken orally, or as ear or eye drops.
Ototoxicity is ear poisoning (oto = ear, toxicity = poisoning) which results from exposure to drugs or chemicals that damage the inner ear or the auditory vestibular nerve, which transmits sound and balance information from the inner ear to the brain. Ototoxicity may affect vestibular function and/or hearing, although with most drugs the auditory receptors are more sensitive to ototoxicity. A large variety of drugs have been associated with ototoxicity, but aminoglycoside antibiotic therapy is the most commonly reported cause of ototoxicity in cats. Due to the potential for compensation, vestibular signs frequently subside once the antibiotic is discontinued. However, deafness is usually permanent.
Metronidazole is a prescription antibiotic used in cats to treat various conditions such as inflammatory bowel disease, nonspecific diarrhea diseases, infections caused by Giardia, and periodontal (gum) disease. The long-term use of metronidazole at high doses may result in a variety of progressive neurological symptoms in cats. This is seen less commonly in cats than in dogs with most of the cat cases reported having involved very high doses of metronidazole. Symptoms may include generalized ataxia, tremors, depression, and even seizures. Once symptoms develop, stopping use of metronidazole is important as continued use may result in irreversible damage or death. Catching the symptoms in the early stages usually results in a complete and quick recovery.
The most common brain tumors in cats are lymphoma and meningiomas. The site of the brain tumour determines the neurological symptoms. Within the cerebellum, a tumour that may occasionally affect younger cats is a medulloblastoma. The brain tumor types typically affecting the brain portion of the auditory vestibular nerve differ slightly from the rest of the brain and include meningiomas and choroid plexus papillomas. Spinal cord tumor is common in cats and the exact symptoms depend on the location of the tumor. A tumor of the spine is classified both with respect to the location and with respect to the tumor type. In general, cats with a tumor of the spine are middle-aged or older (usually over six years of age).
Thiamine Deficiency Thiamine, also known as vitamin B1, is a water-soluble vitamin necessary for normal carbohydrate and amino acid metabolism. Thiamine deficiency causes a progressive brain disease in cats and can be due to a variety of causes like a diet high in fish. Affected cats often demonstrate a period of anorexia before the onset of neurological symptoms. The symptoms usually derive from more than one location, but vestibular symptoms are the most common. Generalized ataxia, occasional vertical nystagmus, no blink response, unequal size of the pupils, and episodes of severe vestibular symptoms are typical. There may also be evidence of head drop, muscle weakness, and fixed, dilated pupils. The condition can progress to seizures, coma, and death.
There are so many possible causes of ataxia, not all of which are listed above, that making an accurate diagnosis can be difficult. A variety of tests can be performed like a complete blood count for possible cancer growth; a biochemical profile and urinalysis for how the organs are functioning; an examination of the middle ear for polyps or infection; a cerebrospinal tap for infection; a CT scan of the middle ear; an x-ray or ultrasound for brain or spinal tumors; or tests for parasites, bacteria, fungi, or viruses. For diagnosing cats with subtle symptoms, there is a way to draw out additional indicators. Maintaining balance when standing in the stationary position requires inputs from the cerebellar, vestibular, and sensory systems. Cats with cerebellar ataxia usually can’t maintain normal balance when standing in the stationary position without taking a wide-based stance and they often sway or even stumble. Cats with vestibular or sensory ataxia can be blindfolded to take away visual input which makes them depend on their vestibular and sensory systems. If one of those systems is affected being blindfolded will cause the cat to become unstable and start to sway or lose balance.
Treatment of ataxia will depend on the root cause. Pain management, supportive care, and making the environment safe are typical. Some causes of ataxia can’t be cured or cats may experience symptoms that progress and may eventually need euthanasia. In the case of Cerebellar Hypoplasia, for instance, there is no cure but these cats can live a normal life with home modifications. This form of ataxia is not painful and the cats compensate for the wobbles from the time they are born. Depending on the severity of symptoms you may want to prevent access to stairs, move the litter box to an area with easy access and use a litter box with high sides for support, use raised food and water bowls for ease when eating, or provide rugs in hard floor areas for grip when walking. Cats with ataxia should never be allowed outside as they will not be able to properly defend themselves against attack.
Phew! I know that was a lot. Believe it or not, though, that was only scratching the surface of ataxia in cats. Hopefully, though, it gave you a better understanding of what it means to be a wobbly cat and some of the more common causes for the wobbles. If there is only one thing you walk away with, I would you hope you understand that a wobbly cat is still a cat in need of love and a home. As in the case of my cat Hemmy, most of the time you can’t even tell he is “special needs.” However, even in more severe cases like Little Man, the cats still lead happy lives and bring joy to your world. So many times wobbly cats are euthanized under the assumption they are in pain or they will be too much work or they are unadoptable. It breaks me heart to think Hemmy might have been euthanized if he had ended up in the hands of someone who didn’t understand. Always make sure to research and ask questions before deciding you know the answer. Share this post so we can teach people about wobbly cats!
Some great wobbly cat Instagram accounts to follow!
Information for this post was compiled from the following sources:
The Wobbly Cat. Diagnostic and therapeutic approach to generalized ataxia. Jacques Penderis. Journal of Feline Medicine and Surgery. 2009 May; 11(5):349-59. journals.sagepub.com/doi/pdf/10.1016/j.jfms.2009.03.003